Structure-function studies on neurohormone D: activity of naturally-occurring hormone analogues.
The relative potencies of 11 naturally-occurring peptides of the adipokinetic hormone/red pigment-concentrating hormone family (AKH/RPCH-family) have been assessed with respect to increase in heart rate in adult, female American cockroaches, Periplaneta americana, in in vitro and in vivo bioassays. In addition, analogues that lacked the N-terminal pyroglutamate residue or had a free threonine acid at the C-terminus were also investigated. In both bioassays the N- or C-terminal-modified analogues give no or little response suggesting that blocked termini are essential for receptor-binding. In both bioassays the naturally-occurring peptide from the cockroach corpus cardiacum Pea-CAH-I (neurohormone D) is more potent than the second endogenous peptide, Pea-CAH-II. On the basis of this result and previous data it is proposed that neurohormone D is the only physiologically important "true" cardioactive peptide. The dose-response curves of the other peptides indicate that in octapeptides, amino acid residues at positions 2, 6, and 7 are important for receptor-recognition, and that decapeptides are not as effective as octapeptides (exception: the peptide Rom-CC-I isolated from the grasshopper Romalea microptera).
Baumann
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Sächsische Akademie der Wissenschaften zu Leipzig und Wissenschaftsbereich Tierphysiologie, Friedrich-Schiller-Universität Jena, German Democratic Republic.
Gäde
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Penzlin
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D000595:Amino Acid Sequence; D000818:Animals; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D007301:Insect Hormones / Q000737:chemistry / Q000494:pharmacology*; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000737:chemistry / Q000494:pharmacology*; D010526:Periplaneta; D013329:Structure-Activity Relationship
D007301:Insect Hormones; D009479:Neuropeptides; C043192:glutamyl-valyl-asparaginyl-phenylalanyl-seryl-prolyl-asparaginyl-tryptophanamide